Passive keyless entry systems and passive keyless start systems are becoming more popular in vehicles. The respective systems offer convenience, ease of use and security. The systems operate based upon the relative locations between the vehicle and a key fob. For example, a user may be able to unlock the doors of a vehicle when the key fob is within a certain distance of the vehicle and start the engine of the vehicle when the key fob is inside the vehicle without having to touch the key fob. Accordingly, accurately determining the relative location between the vehicle and a key fob is important for the respective systems to operate in a consistent manner as expected by end users.
For simplicity and clarity of illustration, descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the exemplary and non-limiting embodiments of the invention described in the subsequent Detailed Description. It should further be understood that features or elements appearing in the accompanying figures are not necessarily drawn to scale unless otherwise stated. For example, the dimensions of certain elements or regions in the figures may be exaggerated relative to other elements or regions to improve understanding of embodiments of the invention.